20.—(1) An aircraft shall not fly unless it is so equipped with radio communication and radio navigation equipment as to comply with the law of the country in which the aircraft is registered or the State of the operator and to enable communications to be made and the aircraft to be navigated, in accordance with the provisions of this Order and any regulations made thereunder.
(2) Without prejudice to paragraph (1), the aircraft shall be equipped with radio communication and radio navigation equipment in accordance with Schedule 5.
(3) In any particular case the CAA may direct that an aircraft registered in the United Kingdom shall carry such additional or special radio communication or radio navigation equipment as it may specify for the purpose of facilitating the navigation of the aircraft, the carrying out of search and rescue operations or the survival of the persons carried in the aircraft.
(4) Subject to such exceptions as may be prescribed, the radio communication and radio navigation equipment provided in compliance with this article in an aircraft registered in the United Kingdom shall always be maintained in serviceable condition.
(5) All radio communication and radio navigation equipment installed in an aircraft registered in the United Kingdom or carried on such an aircraft for use in connection with the aircraft (whether or not in compliance with this Order or any regulations made thereunder) shall—
(a)be of a type approved by EASA or the CAA in relation to the purpose for which it is to be used; and
(b)except in the case of a non-EASA glider which is permitted by article 3(2) to fly unregistered, be installed in a manner approved by EASA in the case of an EASA aircraft and the CAA in the case of a non-EASA aircraft.
(6) Neither the equipment referred to in paragraph (5) nor the manner in which it is installed shall be modified except with the approval of EASA in the case of an EASA aircraft or the CAA in the case of a non-EASA aircraft.